Multichannel AV Preamplifiers are the audio processors used in the best home theater systems because the best setup involves separation between the unit decoding the audio streams and the amplification stages(amplifiers), which must be separate. The best AV Preamplifiers today, in addition to decoding 3D Audio streams (such as Dolby Atmos, DTS:X and AURO 3D), must necessarily incorporate an at least semi-professional acoustic calibration suite.